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Title: LOW-POWER RADIO GALAXIES IN THE DISTANT UNIVERSE: A SEARCH FOR FR I AT 1 < z < 2 IN THE COSMOS FIELD

Abstract

We present a search for FR I radio galaxies between 1 < z < 2 in the COSMOS field. In absence of spectroscopic redshift measurements, the selection method is based on multiple steps which make use of both radio and optical constraints. The basic assumptions are that (1) the break in radio power between low-power FR Is and the more powerful FR IIs does not change with redshift, and (2) that the photometric properties of the host galaxies of low-power radio galaxies in the distant universe are similar to those of FR IIs in the same redshift bin, as is the case for nearby radio galaxies. We describe the results of our search, which yields 37 low-power radio galaxy candidates that are possibly FR Is. We show that a large fraction of these low-luminosity radio galaxies display a compact radio morphology that does not correspond to the FR I morphological classification. Furthermore, our objects are apparently associated with galaxies that show clear signs of interactions, at odds with the typical behavior observed in low-z FR I hosts. The compact radio morphology might imply that we are observing intrinsically small and possibly young objects that will eventually evolve into the giantmore » FR Is we observe in the local universe. One of the objects appears as pointlike in Hubble Space Telescope (HST) images. This might belong to a population of FR I-QSOs, which however would represent a tiny minority of the overall population of high-z FR Is. As for the local FR Is, a large fraction of our objects are likely to be associated with groups or clusters, making them 'beacons' for high-redshift clusters of galaxies. Our search for candidate high-z FR Is we present in this paper constitutes a pilot study for objects to be observed with future high-resolution and high-sensitivity instruments such as the EVLA and ALMA in the radio band, HST/WFC3 in the optical and IR, James Webb Space Telescope in the IR, as well as future generation X-ray satellites.« less

Authors:
; ; ;  [1];  [2];  [3]
  1. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  2. INAF-Osservatorio Astronomico di Torino, Via Osservatorio 20, I-10025 Pino Torinese (Italy)
  3. INAF-Osservatorio Astronomico di Trieste, Via Tiepolo 11, I-34143 Trieste (Italy)
Publication Date:
OSTI Identifier:
21300706
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 696; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/696/2/1103; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; CLASSIFICATION; GALAXY CLUSTERS; LUMINOSITY; MORPHOLOGY; RADIO GALAXIES; RED SHIFT; SATELLITES; TELESCOPES; UNIVERSE

Citation Formats

Chiaberge, Marco, Tremblay, Grant, Macchetto, F Duccio, Sparks, W B, Capetti, Alessandro, and Tozzi, Paolo. LOW-POWER RADIO GALAXIES IN THE DISTANT UNIVERSE: A SEARCH FOR FR I AT 1 < z < 2 IN THE COSMOS FIELD. United States: N. p., 2009. Web. doi:10.1088/0004-637X/696/2/1103; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Chiaberge, Marco, Tremblay, Grant, Macchetto, F Duccio, Sparks, W B, Capetti, Alessandro, & Tozzi, Paolo. LOW-POWER RADIO GALAXIES IN THE DISTANT UNIVERSE: A SEARCH FOR FR I AT 1 < z < 2 IN THE COSMOS FIELD. United States. https://doi.org/10.1088/0004-637X/696/2/1103; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Chiaberge, Marco, Tremblay, Grant, Macchetto, F Duccio, Sparks, W B, Capetti, Alessandro, and Tozzi, Paolo. 2009. "LOW-POWER RADIO GALAXIES IN THE DISTANT UNIVERSE: A SEARCH FOR FR I AT 1 < z < 2 IN THE COSMOS FIELD". United States. https://doi.org/10.1088/0004-637X/696/2/1103; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21300706,
title = {LOW-POWER RADIO GALAXIES IN THE DISTANT UNIVERSE: A SEARCH FOR FR I AT 1 < z < 2 IN THE COSMOS FIELD},
author = {Chiaberge, Marco and Tremblay, Grant and Macchetto, F Duccio and Sparks, W B and Capetti, Alessandro and Tozzi, Paolo},
abstractNote = {We present a search for FR I radio galaxies between 1 < z < 2 in the COSMOS field. In absence of spectroscopic redshift measurements, the selection method is based on multiple steps which make use of both radio and optical constraints. The basic assumptions are that (1) the break in radio power between low-power FR Is and the more powerful FR IIs does not change with redshift, and (2) that the photometric properties of the host galaxies of low-power radio galaxies in the distant universe are similar to those of FR IIs in the same redshift bin, as is the case for nearby radio galaxies. We describe the results of our search, which yields 37 low-power radio galaxy candidates that are possibly FR Is. We show that a large fraction of these low-luminosity radio galaxies display a compact radio morphology that does not correspond to the FR I morphological classification. Furthermore, our objects are apparently associated with galaxies that show clear signs of interactions, at odds with the typical behavior observed in low-z FR I hosts. The compact radio morphology might imply that we are observing intrinsically small and possibly young objects that will eventually evolve into the giant FR Is we observe in the local universe. One of the objects appears as pointlike in Hubble Space Telescope (HST) images. This might belong to a population of FR I-QSOs, which however would represent a tiny minority of the overall population of high-z FR Is. As for the local FR Is, a large fraction of our objects are likely to be associated with groups or clusters, making them 'beacons' for high-redshift clusters of galaxies. Our search for candidate high-z FR Is we present in this paper constitutes a pilot study for objects to be observed with future high-resolution and high-sensitivity instruments such as the EVLA and ALMA in the radio band, HST/WFC3 in the optical and IR, James Webb Space Telescope in the IR, as well as future generation X-ray satellites.},
doi = {10.1088/0004-637X/696/2/1103; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
url = {https://www.osti.gov/biblio/21300706}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 696,
place = {United States},
year = {Sun May 10 00:00:00 EDT 2009},
month = {Sun May 10 00:00:00 EDT 2009}
}